Brett Meyer commented on an issue
Hibernate ORM / Bug HHH-7081
"Second pass" information can get lost during configuration if a component has a nested component, leading to ConcurrentModificationException during configuration.
I have an environment with an entity A which contains a map of components/elements B. Each B has a component C which refers (many-to-one) to an entity D.

During configuration and second-pass compile, I get this call sequence:

Configuration.originalSecondPassCompile at line 1716 calls MapBinder$1(CollectionSecondPass).doSecondPass

doSecondPass at line 6...